The present invention relates to an electrically controlled exposure for a camera which incorporates therein, or is capable of mounting thereon, an electronic flash device.
Hitherto, for example in U.S. Pat. No. 3,535,989 and U.S. Pat. No. 3,535,991, an electrically controlled exposure in a camera of the type, which is prepared for flash photography when the brightness of an object is lower than a predetermined level and for day-light photography with automatic exposure control when the brightness of the object is higher than the predetermined level, is well known. For the selection of the flash photography and the day-light photography, the conventional cameras are provided with mechanical switching means coupled with an electromagnet which is actuated depending on the output of a brightness detecting circuit. However, such mechanical switching means has a complex construction, which increases their cost of manufacturing. Moreover, for flash photography, a specific shutter speed is always selected to ensure synchronization between the exposure and the flashing of the flash tube. However, the selection of the specific shutter speed will result in an under-exposure due to an insufficient amount of light emitted from the flash tube if the shutter is erroneously released when the main capacitor of the flash device has not been charged up to a level for firing the flash tube to emit a sufficient amount of light.